Boiler penthouse

ABSTRACT

A pressurized penthouse which is joined to the top of a boiler and which retains internal pressure even when the boiler expands substantially more than the penthouse. The overhang of the penthouse is provided at each corner with corrugations which permit expansion of the boiler without the development of leaks in the penthouse.

United States Patent DH l l inventor Martin D. Bernstein Bro-x, N.Y.Appl No 853,903 Filed Aug. 28. 1969 Patented July 13, I971 AssigneeFoster Wheeler Corporation Livingston, NJ.

BOILER PENTHOUSE 5 Chime, Drawing Figs.

[1.8. CI 2/494 F22!) 37/36 l 22/6 A.

[ 5 6 Referenees Cited UNITED STATES PATENTS 3 479 994 ll/l969 Kreidereta]. r. l22/494 [986,667 l/l935 Bailey l22/235 Primary Examiner---Kenneth W Sprague At!0rneys-J0hn E, Wilson, John Maier, Ill and MarvinA.

Naigur ABSTRACT: A pressurized penthouse which is joined to the top of aboiler and which retains internal pressure even when the boiler expandssubstantially more than the penthouse. The overhang of the penthouse isprovided at each corner with corrugations which permit expansion of theboiler without the development ofleaks in the penthouse.

PATENTED JUL I 319m 3.592171 sum 3 BF 3 IIIIIIIlI/III/l/j/LIl/[LllI/II/IITIIII/ITII INVEN'I ()R 28 FIG 4 BY MARTIN D. BERNSTEIN 54/1JOHN 5 WILSON ATTORNEY BOILER PENTHOUSE BACKGROUND OF THE INVENTION In amodern large boiler, pipes and/or other conduits which join several ofthe boiler sections often project upwardly over the top of the boiler.To prevent heat losses, the conduits are often insulated by means of apenthouse which covers the top of the boiler.

In such an arrangement. problems have been encountered because gaseswhich are generated within the boiler escape into the penthouse. Thisproblem is serious because the gases are corrosive. To prevent suchleakage, the interior of the penthouse is often pressurized so that ifthe interiors of the boiler and penthouse communicate, the corrosivegases will not pass into the penthouse.

Maintaining pressure inside of the penthouse is complicated by the factthat the boiler expands more than does the penthouse during operation.The difference in the degree of expansion between the boiler andpenthouse is due to the fact that the penthouse is insulated from thehigh boiler temperatures. Therefore, a rise or fall in boilertemperature will not induce a corresponding significant temperaturechange in the penthouse. Consequently, the boiler expands and contractsduring operation much more than the penthouse and thus joining theboiler and penthouse so that no leakage develops between them is often adifficult if not impossible task.

A type of penthouse which is in common use today is one which projectsoutwardly beyond the boiler and which uses a flat horizontal bottom wallextending inwardly from its sides to the outer wall of the boiler. Anexpansion hump which may be more or less Ushaped is usually provided inthe horizontal wall of the penthouse so that it passes completely aroundthe boiler. Such a joint will permit the sidewalls of the boiler to pushoutwardly against the bottom wall of the penthouse without all of thedisplacement at the inner portion to the bottom wall being transmittedto the outer portion thereof.

It must also be appreciated that in a large boiler installation. boththe penthouse and the boiler are generally hung from structural membersby elements which are heated by heat conducted from the associatedboiler or penthouse. Since the elements which connect the boiler tothose structural members will be heated to a higher temperature than thetemperature of the elements which connect the penthouse to such members.the boiler will sag downwardly more than the penthouse during operation.Moreover, for any given increase in boiler tem perature the boiler willdescend more than the penthouse because the penthouse is insulated fromthe boiler. so that its sidewalls will not expand downwardly as much asthe boilers sidewalls. This relative motion between the penthouse andboiler is also compensated for somewhat by the expansion hump in thebottom wall ofthe penthouse.

One problem which has not been solved satisfactorily is due to the factthat the bottom wall of the penthouse, being shaped generally as arectangle, is made up of straight segments. each of which is expandedalong its length as well as being pushed outwardly under the action of aheated boiler. The longitudinal expansion of the straight segmentscreates substantial straining in the corners of the bottom wall, thatis. in the areas where the straight segments meet. In the past this hascaused leakage to develop between the penthouse and boiler and/orbetween the penthouse and atmosphere.

SUMMARY It is an object of the present invention to overcome theproblems found in the prior art such as those discussed above. Thebottom wall of the penthouse is provided with corrugations adjacent tothe corners thereof to permit relative movement between the boiler andthe penthouse without the development of leakage between the penthouseand the atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective fragmentaryview of a portion ofa penthouse made in accordance with the presentinvention;

FIG. 2 is a fragmentary view, partly in section. of the presentpenthouse mounted on top of a boiler;

FIGv 3 is a fragmentary plan view of the portion of the presentpenthouse which is shown in FIG. I; and

FIG. 4 is a fragmentary plan view similar to FIG. 3. but showing anotherembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The structure which isshown in some detail in FIG. 1 may be incorporated in a penthouse 10.which, as shown in FIG. 2, is adapted to be mounted on top ofa boiler12, to insulate the piping and/or other conduits which pass over the topof the boiler from the atmosphere to thereby prevent heat loss. Thepenthouse 10 has outer walls 14 which project vertically. as do outerwalls 16 of the boiler 12.

It has already been explained that when the boiler 12 is heated. thewalls I6 expand outwardly and because the boiler 12 is suspended fromoverhead structure such as beam 18 by elements such as tie rods 20 whichelongate when heated by the boiler, the walls 16 drop somewhat inrelation to the outer walls 14 of the penthouse Ill. (The penthouse ofcourse. picks up little of the boiler heat so that its associated tierods 22 do not elongate significantly.) This relative movement and theresultant adverse effect on the penthouses capacity to prevent leakageof the pressurized air within has been ameliorated somewhat by aU-shaped hump 24 in the penthouse 10 which encircles the boiler 12between the penthouse sidewall 14 and boiler sidewall 16. The hump 24has a top portion 26. a downwardly extending inner sidewall 28 and adownwardly extending outer sidewall 30. The sidewalls 28 and 30 mergewith the top portion 26 and extend downwardly to the bottom wall 32which has an inner portion 34 and an outer portion 36. The inner portion34 of the wall 32 has an inner edge 35 which is joined to the sidewall16 of the boiler 12 as shown in FIGS. 2 and 3. The outer portion 36 ofthe wall 32 extends outwardly to the outer wall 14 of the penthouse 10.It will be apparent that the bottom wall 32 is made up of four straightsegments which form a rectangle.

It also has already been explained that when the walls [6 of the boiler12 expand they are moved outwardly as they increase in width. Anincrease in width of the sidewalls l6 tend to elongate each of thestraight segments of the inner portion 34 of the bottom wall 32 of thepenthouse II] and consequently each straight segment of the outerportion 36 of the bottom wall 32. This tends to create large stresses inthe corner areas 38 (FIGS. 1 and 3) which can result in failure and thusleakage of the pressurized air within the penthouse 10 either at thoseareas or between the edge 35 and the boiler sidewall 16. It is alsopossible that stresses will be transmitted over the outer portion 36sufficiently to cause a leak between it and the outer wall 16 or betweenthe outer wall 14 and the top deck of the penthouse 10. And it is alsopossible for such stresses to cause failure between the straightsegments of the sidewall 14.

As shown in FIG. 3. a point F on the top 26 of the hump 24 will moveoutwardly to F because of the outward expansion of the boiler 12 at theouter walls 16. The hump 24 will prevent most of this outwarddisplacement from being transmitted to the outer portion 36 of thebottom wall 32 of the penthouse 10. Consequently a point D on the outerperiphery of the top portion 28 will move substantially only along aline which is parallel to the sidewall M5 to settle at D.

The hump 24 has outer corners 40 and inner corners 42. A point C closeto a corner 40 of the hump 24 will move outwardly in a direction at anangle to the sidewall Hi to point C as the outer side 30 expands to theposition shown in dashline in FIG. 3 due to the longitudinal expansionof the two contiguous straight segments of the bottom wall 32 and theresultant outward component of expansion in the corner area 38. Thisaction creates a large degree of distortion in the bottom wall 32 in thecorner area 38. To prevent this distortion from being transmitted out tothe outer wall 14 of the penthouse to severely strain the penthouse l0,corrugations 44, 46, 48 are provided. These corrugations are preferablycurved so that they are in a position to take up strains on the cornerarea in the direction generally diagonal to the rectangle formed by thebottom wall 32. The amount of distortion is probably less at thecorrugation 46 than it is at the corrugation 44 and the distortion atthe corrugation 48 is probably less than the distortion of thecorrugation 46. The distortion is probably greatest at the centralportion of each corrugation as they move to the position shown indot-dashline in FIG. 3.

In the preferred embodiment, auxiliary corrugations 50 and 52 extendperpendicular to the sidewalls 16 of the boiler 12 in the penthousebottom wall 32 close to the corner areas 38. These corrugations help topermit the outer portion 36 of the bottom wall 32 adjacent to thesidewall to move toward the corner 40 without transmitting thisdistortion to the outer wall 14 of the penthouse 10. If the bottom wall32 is to be provided with a maximum ability to withstand distortion inthe corner area 38 thereof. added corrugations 54, 56, 58 and 60 can beprovided as shown in FIG. 4, so that each of the curved corrugations arecontiguous with one another. Similarly, corrugations 62 and 64 can beprovided in the outer portion 36 of the bottom wall 32 perpendicular tothe outer wall 30 of the hump 24 to further prevent the linear expansionof the sidewall 16 of the boiler 12 from being transmitted to the outerwall 14 ofthe penthouse ll] and to prevent separation of the outer wall14 from the penthouse [0, To prevent failure of the hump 24 between itscorners 40 and 42 and to take up some of the diagonal strain in thecomer area 38 along with the curved corrugations 44, 46 and 48, acorrugation 66 is provided in the top 26 of the hump 24,

It is to be understood that the foregoing describes only one preferredembodiment of the present invention and that other embodiments will beapparent to a person of ordinary skill in the art which will be withinthe scope of the present invention.

1 claim:

IV A component for a boiler penthouse which penthouse is adapted tocover a boiler having a sidewall, said component having an inner edgewith straight portions and corners to permit said edge to be connectedwith said sidewall of the boiler, a corrugation in said componentadjacent to one of said corners to prevent distortion induced in saidcomponent by expansion of said sidewall in a direction generallydiagonal to said corner from causing rupture in said component, and anauxiliary corrugation in said component extending generallyperpendicular to said edge,

2, The component defined in claim 1 wherein said auxiliary corrugationis adjacent to an end of said corrugation adjacent to said corner 3. Thecomponent defined in claim I wherein said corrugation adjacent to saidcorner is one of a plurality of such corrugations each being laterallyspaced from the others, with one of the ends of each adjacent to saidauxiliary corrugation.

4. The component defined in claim 3 wherein said corrugations adjacentto said corner are curved about said corner,

5. The component defined in claim 4 further comprising another auxiliarycorrugation, said auxiliary corrugation being positioned adjacent to theother ends of said corrugations adjacent to said corner.

1. A component for a boiler penthouse which penthouse is adapted tocover a boiler having a sidewall, said component having an inner edgewith straight portions and corners to permit said edge to be connectedwith said sidewall of the boiler, a corrugation in said componentadjacent to one of said corners to prevent distortion induced in saidcomponent by expansion of said sidewall in a direction generallydiagonal to said corner from causing rupture in said component, and anauxiliary corrugation in said component extending generallyperpendicular to said edge.
 2. The component defined in claim 1 whereinsaid auxiliary corrugation is adjacent to an end of said corrugationadjacent to said corner.
 3. The component defined in claim 1 whereinsaid corrugation adjacent to said corner is one of a plurality of suchcorrugations each being laterally spaced from the others, with one ofthe ends of each adjacent to sAid auxiliary corrugation.
 4. Thecomponent defined in claim 3 wherein said corrugations adjacent to saidcorner are curved about said corner.
 5. The component defined in claim 4further comprising another auxiliary corrugation, said auxiliarycorrugation being positioned adjacent to the other ends of saidcorrugations adjacent to said corner.